Half to howard



(ModeL) 3 Sheets-Sheet 1,

0. ROOT.

ANNUNUIATOR AND OPERATING TABLE FOR TELEPHONE LINES.

251.640. Patented Dec; 2 1881.

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(ModeL) 3 Sheets-Sheet 2 0. M. ROOT.

A ANNUNGIATOR ANDVOPERATING TABLE FOR TELEPHONE LINES.

No. 251,640. Patented Dec. 27,1881

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(ModeL) 3 Sheets-Sheet 3.

O. M. ROOT.

ANNUNGI ATOR-AND OPERATING TABLE FOR TELEPHONE LINES. N0. 251,q40.- E Patented Dec. 27,1881.

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I UNITED I STATES PATENT OFFICE.

CHARLES ROOT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE- HALF TO HOWARD U. ROOT, OF SAME PLACE.

ANNUNCIATOR AND OPERATING-TABLE FOR TELEPHONE-LINES.

SPECIFICATION forming part of Letters Patent No. 251,640, dated December 27, 1881. Application filed September 12, 1881. (Model.)

To all whom it may concern:

, Be it known that 1, CHARLES M. Roor, a

citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Annunciators and Operating-Tables for Telephone-Lines, of which the' following is a specification.

The main object of my invention is to so construct a telephone-annunciator and to so com- IO bine the line-wire and ground -connecti0ns therewith that a subscriber calling the central officewill know whether his signal has been received there, or whether the line or instrument is defective in some particular whichprevents the transmission of the signal, afurtherobject being to provide simple and efficient means for answering the call, and to dispense with the use of the usual plugs or springjacks for maintaining ground connections. These objects I attain in the manner which I will now proceed to describe, reference being had to the accompanying drawings, in which Figure 1, Sheet 1, is a diagram showinga telephone instrument and the annunoiator therefor at the central office; Fig. 2, an enlarged-view of said annnnciator asordinarily constructed; Fig. 3, a view of my improved annunciator and its connections; Figs. 4 and 5, Sheet 2,. views similar to Fig. 3, but with some of the parts in different positions; Fig. 6,

a plan view of the operating-table used in connection with the annunciator; and Figs. 7 and 8, Sheet 3, views of a modification of part of my invention.

1 In Fig. 1, A represents the call-box of the usual Bell telephone apparatus, and B the annunciator at the central office, said annunciator comprising an electro magnet, D, with armature E, and a pivoted arm, F, carrying a 4 plate, F, the latter having a number corresponding with the number of the instrument with which the annunciatoris connected. The normal position of the arm Fis that indicated in Fig. 2, the upper hooked end of the arm engaging with the armature E, and being retained thereby until a call is sent over theline, when the armature is attracted and the arm F released and allowed to fall, so as to exposethe numbered plate F. .Usually the line isv carried from the clectro-inagnet to the ground,

and as long as this ground-connection is maintained and a current sent over the line the bell on the call-box A will ring, the groundconnection being broken by the operator at the central office prior to answering the call. The

main objection to this arrangement is that it affords no means whereby the subscriber can definitely determine whether or not his signal or call has been received at the central office. For instance, the line may be short-circuited Go by an accidental ground-connection between the telephone and the central office, in which case, although the bell on the call-box A would continue to ring during the time that the call was being sent, the signal would not reach the central office at all, the subscriber, however, being ignorant of the disturbing condition, and hence likely to charge the operator at the central office with inattention or neglect in failing to answer the call. To remedy this ob- 7o jection I propose to so construct the annunciator that the ground-connection will be automatically broken after the call has been continued for a certain lengthof time, the hell on the call-box ceasing to ring, so that the caller will at once know that his signal has been received; or, if the bell does not cease ringing after the lapse of the stated time, the subscriber will know that the line or instrument is not in working condition, and can. notify the proper oflicer to have it attended to.

Figs. 2, 3, and 4 show the annunciator as constructed for carryin g out my invention, the magnets D, armature E, and annunciator-arm F being the same as usual, with the exception 8 5 that the post G, to which the armature is hung, is insulated from theframeJandhas a groundwire, 00. Theline, instead of being carried from the magnet D to the gr0und,asin the usualin strument, is connected to the frame J at a, at 0 which point a spring, I), is also conneotedto the frame, this spring being acted upon by a pin, d, on the annunciator-arm in sucha manner that the spring is held up, as shown in Fig.

3, when the arm is raised; but when the arm 5 falls, as shown in Fig. 4, the spring is permitted to come into contact with one of the teeth of a wheel, 6, which is mounted on a shaft, f,

the latter extending in front of a row of annunciators, and being rotated in the direction of the arrow by clock-work or similar means, so that the contact between the spring I) and the toothed wheel e is of limited duration, the P0- tation of the wheel soon freeing the spring and permitting it to assume its normal position, as

shown in Fig. 5.

The shaft f is insulated from the frame J and has a ground-connection, y, and a wire, to, extends from the j auction-wire of the magnets D to a block, 1', forming part of an operatin g-table, the construction of which will be understood on reference to Fig. 6. This operating-table consists of an outer annular plate, at, an inner plate or disk, n, and an intermediate annular plate composed of a series of blocks, '5, each insulated from the others, and each connected-to one of a series of annunciators in connection with which the operating-table is to be used.

Theouter plate, m,is connected-to asuitable current-generator, and the inner plate, a, is connected to a transmitter, both'the outer and inner plates being separated orinsulated from the intermediate plate but any one of the blocks 73 composing the latter plate can be connected with either of the plates at or n by inserting aplug, 8, into the space between said plate andthe block i.

The operation of the device is as follows:

When a call issent over the linefrom a subscriber to thecentral office the circuit is'completed through the magnet D, and through the frame J, annunciator'arm F, armature E, and

insulated post G, to the ground at w, as shown in Fig.3. The armature beingthereby attractedto the magnet, the annunciator-arm F is released and falls, thereby cuttin g out the ground connection or and shunting the circuit to the spring I), and thence through the wheele and shaftfto the ground at y, as shown in Fig. 4.. The bellon the call-boxA of the telephone continues to ring as longas this circuitiscomplete; but the revolution of the wheel 6 soon releases the spring I) from contact therewith, thereby breaking the circuit, as shown in Fig. 5. As soon as the circuit is broken the bell on the call-box A ceases to ring, and the subscriber knows that his signal has been properly received at the central office. The operator at the central office then proceeds to answer the call by inserting the plug 8 between the outer thus rung in answer. The operator then shifts theplug s from the space between the blocki and the outer plate, m, to the space between said block 2' and the inner or transmitter plate, a, the line being then in condition for the transmission of speech between the central oiiice and the subscriber, in order that the instructions of the latter may be received. Connections are afterward made in the usual way between the subscribers line and that of any to communicate.

other subscriber with whom the first may wish The raising of the annunciator-arm F again grounds the line through the connection w,in readiness for a further call.

When a subscriber calls the central office and the bell on the call-box does not cease 'to I ring after the expiration of the stated period, it will indicate that the line or instrument is out of order, and'that a failure to answer the call is not due to the inattention or neglect of the operator at the central office, who is thus relieved from much of the unjust censure which is caused by the present method of making connections at the annunciator, prompt attention, moreover, being called to defects in the line or telephone-instrument, so that said defects can be at once attended to. The advantages of this feature of my invention are enhanced when two or more telephone-instruments are worked on a single line, for in this case when there is a defect in the line it will be-indicated to any one making a call, and the annoyance of all of the subscribers on the line by prolonged attempts to signal the central office on the part of one of the subscribers will be prevented.

The operating-table above described is a simple and-compact device,-which permitsthe prompt answering of a'call, the insertion of a-single plug being all that is necessary to connect the line with the current generator or the-transmitter, the usual cord-connections and spring-jacks and independent ground-plugs being entirely dispensed with.

Straight plates instead of annular plates may be used in making the operating-table, if desired, although the annular plates are preferred on the score of greater compactness.

Other means than that shown of breaking the circuit through the line 3 may be employed. For instance, each wheel 0 may be combined with simple escapement mechanism, and may be set in motion by the tension of thespring b acting thereon, the speed of movement being shown another .modification of my invention,

in which the spring b and wheel e are dispensed with, the said wheel e being replaced by a lever, 0, one arm, a, of which is in the form of a segmental enlargement, having in its periphery a block, 6 of insulating material. This lever is acted upon by a light spring, a, the tendency of which is to retain the lever in the position shown in Fig. 7. When the arm F of the. annunciator falls, however, it drops onto the end of the arm 0 of the lever, and the weight of the arm F overcomes the tension of the spring 6 and causes a movement of the lever to the position shown in Fig. 8, the ground-wirey being then cut out by the insulated block 0. During the time that the lever 0 is being moved from one position to the other the current passes to the ground through the arm F, the lever, and the wire y, and on the restoration of the arm F to its elevated position the spring 6 restores the lever to the position shown in Fig. 7.

I claim as my invention- 1. The combination of a telephone-annouciator, a line-wire, a permanent ground-connection, a ground-connection having an auto-' matic circuit-breaker therein, and means, substantially as described, wherebyon the fall of 3. The within-described telephoneoperatingtable, comprising the current-plate m, transmitter-plate n, and intermediate plate composed of blocks 1', insulated from each other and from the plates m and n, and each connected to the line-wire, as set forth.

4:. The combination of the annuneiator, the line-wire, the operating-table comprising the current-plate m, transmitter-plate n, and intermediate insulated blocks, i, the wires w,' whereby the blocks 73 are connected to the respective lines, and as set forth. i In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

the circuit-making plug 8,

CHAS. M. ROOT.

Witnesses:

HARRY DRURY, HARRY SMITH. 

